This repo stores the AMP versions that are being served by AMP CDNs in configs/versions.json. It also hosts the deployment and patching workflows for the release on-duty engineer¹.

The following AMP CDNs are managed by this repository:

• ampjs.org (OpenJS Foundation owned, Cloudflare hosted)
• cdn.ampproject.org (Google owned and hosted)

This README contains instructions for the releases on-duty engineer. To learn more about AMP releases, please see release documation at https://github.com/ampproject/amphtml/tree/main/docs.

Nightly releases are cut, built and deployed automatically.

Releases are promoted to channels by updating configs/versions.json in a PR. These PRs are created on a schedule and assigned to the on-duty engineer, to be approved and merged.

Once merged, the CDNs will pick up the new versions. It takes about 15-30 minutes for cdn.ampproject.org to take effect, and about 1 minute for ampjs.org.

As a summary, promotions run on a weekly schedule:

* lts promotions occur every 2nd Monday of the month.

For more information about schedules and channels, see https://github.com/ampproject/amphtml/blob/main/docs/release-schedule.md.

To cherry-pick a release, run the Cherry-pick a release workflow. It asks for the AMP version to fix, as well as the commit shas to cherry-pick. For multiple commits, separate the shas with a space.

How it works: the workflow pushes a new branch to amphtml. CircleCI will pick up that branch and build the release. Once built and uploaded to ampjs.org, the CircleCI job will trigger the promote workflow.

It takes about 30 minutes from triggering the cherry-pick to creating a promote PR. The PR should promote the cherry-picked AMP version in all the channels that had the faulty AMP version. To complete the cherry-pick, approve and merge the PR.

Like regular promotions, it takes about 1 minute once merged for ampjs.org to begin serving the patched release. However, cdn.ampproject.org takes between 30 and 90 minutes.

To resolve merge conflicts, cherry-pick the release locally:

1. check out the tag: git checkout ${amp_version}
2. switch to a new branch: git switch -c amp-release-${amp_version}-fix
   (make sure that the branch starts with amp-release-)
3. cherry-pick the fix: git cherry-pick -x ${shas}
   (make sure to include the -x flag)
4. resolve any merge conflicts
5. push branch to remote: git push https://github.com/ampproject/amphtml.git

To roll back a release, find the promote PR and revert it. Do not modify configs/versions.json manually.

Like regular promotions, it should take between 15-30 minutes for the roll back to take effect on cdn.ampproject.org, and 1 minute on ampjs.org.

If any of the workflows fail, the on-duty engineer will be notified by a GitHub issue. Please resolve the failures in order to stick to the promotion schedule as close as possible.

Promotion workflows can be triggered manually from the Actions tab on this repository. A successful run will result in a PR.

To request access to this repo, reach out to @ampproject/wg-infra.